论文标题
单元素阶段破坏奇偶校验：铁电样元素极性金属
Parity-breaking in single-element phases: Ferroelectric-like elemental polar metals
论文作者
论文摘要
文献中已经证明了基于二元和三元化合物的极性金属。在这里，我们提出了一个针对铁电元素极性金属的设计原理，并将其与真实材料相关联。设计原则是，作为一种元素极性金属，原子应在具有极地空间群的晶体中至少占据两个不等的Wyckoff位置，在该晶体中，反转对称性会自发损坏。 According to this rule, we propose the first class of potential ferroelectric-like elemental polar metals in a distorted α-La-like structure with a polar space group P63mc in which two inequivalent Wyckoff positions 2a (0, 0, z) and 2b (1/3, 2/3, z) are occupied by group-V elements (phosphorus, arsenic, antimony, and bismuth).基于第一原理计算的分析表明，在p63/mmc对称性中，孤对驱动的非平面相驱动的极性失真引起动态稳定的极相，其中两个不等的Wyckoff位置2A（0，0，0，0，0）和2C（1/3，2/3，2/3，1/4）。这种类似铁电的过渡涉及从金属状态到半金属状态的过渡。相对于它们相应的地面相，这些预测的极相具有亚稳定性。此外，由于小组V原子之间的Wyckoff位置的不等值，因此发现了离子键合特征。我们的工作开辟了一条单元均等阶段的途径。
Polar metals based on binary and ternary compounds have been demonstrated in literature. Here, we propose a design principle for ferroelectric-like elemental polar metals and relate it to real materials. The design principle is that, to be an elemental polar metal, atoms should occupy at least two inequivalent Wyckoff positions in a crystal with a polar space group, where inversion symmetry is spontaneously broken. According to this rule, we propose the first class of potential ferroelectric-like elemental polar metals in a distorted α-La-like structure with a polar space group P63mc in which two inequivalent Wyckoff positions 2a (0, 0, z) and 2b (1/3, 2/3, z) are occupied by group-V elements (phosphorus, arsenic, antimony, and bismuth). Analyses based on first-principles calculations indicate that the dynamically stable polar phase results from a lone pair driven polar distortion of the nonploar phase in P63/mmc symmetry where two inequivalent Wyckoff positions 2a (0, 0, 0) and 2c (1/3, 2/3, 1/4) are occupied. This ferroelectric-like transition involves a transition from a metallic state to a semimetallic state. These predicted polar phases are metastable with respect to their corresponding ground phases. Moreover, ionic bonding characters are found due to the inequivalence in Wyckoff positions between group-V atoms. Our work opens a route to single-element parity-breaking phases.
